Stability of host plant resistance to sorghum charcoal rotSIndiraauthorB SRanaauthorB BReddy authorN G PRao authorThe 29 entries, including elite hybrids, cultivars, parents and resistant stocks, were evaluated for resistance to Macrophomina phaseolina in 4 environments covering rabi and kharif seasons. Artificial epiphytotic conditions were created by the tooth-pick method. Despite significant genotype × environment interactions varietal differences persisted. There was no host immunity but SPV-34, CSH-9 and 36B among the improved lines developed at the All-India Coordinated Sorghum Improvement Project and 6-39, 8-55 and SC 120-14 among the basic stocks were highly resistant. CSH-9, 36B and 6-39 were av. and 8-55 and SC 120-14 were above av. in stability of disease resistance. The seasonal change in host plant resistance of some of the cultivars appears due to their photoperiodic sensitivitySorghum1983Indian Phytopathological SocietyArticle